Rotary pump



March 6, 1928. 1,661,325

w. I. DERRICK ROTARY PUMP inal Filed May 4. 1922 /72 gwuento'c W IrDlRP/CK,

553m 7; MQCZ attorney Patented litter. Q, 1928.

WILLIAM DERRICK, DAWNIEOBT, EGEVA.

PUMP.

original application filed May 4, 1922, Serial No. 558,452. Divided and this application filed July as,

llklfit'l.

This invention relates to rotary pumps, and more particularly to the class of pumps employing a rotor in a housing.

An object of this invention is to provide a pump with a rotor which, when the pump is operating and building up pressure, will automatically balance itself axially so that it will not bear on the casing and consequently will reduce wear and lengthen the life of the pump.

This application is a division of my application. Serial No. 558,452, filed May a, 192:2.

lln pumps oi the type wherein a rotor engages water in an annular passage the rotor has a more or less close working fit between portions of the opposite walls of the casing in which it is mounted, which is necessary to cut ofi' any substantial communication between the annular passage and the central portion of the chamber formed by the cusing walls. A small amount of liquid, however, will work through between the rotor and side walls, and if, due to imperfect lit, a greater amount of liquid escapes to the center of the chamber on one side of the rotor than the other, an excess pressure is built up upon that side tending to push the rotor still :t'arther toward one wall of the casing and thus increase the misalinement and cause excessive friction between the rotor and casing.

it is an object of this invention to pro vide a construction in which unequal pres sures cannot be created upon opposite sides of the rotor, so that the rotor will be balanced axially when running.

Another objectof this invention is to provide a construction in which the contiguous walls of casing and rotor have a packing held between them and yet these surfaces have a relatively large contact, so that accurate positioning of the casing walls and rotor with respect to each other is possible.

Other objects will be apparent from the following description in connection with the annexed drawings.

In said annexed drawings:

Figure l is an elevation partially broken away to show a portion of the rotor and casing in section;

Fig. 2 is a central transverse vertical section showing the cover detached;

Fig. 3 is a View of the rotor;

Fig. 4 is a section on an axial plane through the roto Serial No. 12s,365.

5 is a side elevation of the casing; and

Fig. 6 is an enlarged view of that portion of the rotor and easing shown in section in Fig. 1.

Referring to the drawing, the casing body 1, base 2, and shaft supporting bracket 3 are cast integrally. The casing l is saucer shaped and has a peripheral rim 4 having a fiat peripheral side face 5, an internal peripheral channel 6,- the outer wall of which may be formed by an inwardly extending rib 7 having a cylindrical inner edge. The web portion of the casing body has upon the inner face thereof a relatively low annular rib 8 concentric with the rim l. The casing body 1 has an axial integral tubular boss 9 on the outer side thereof. The bracket 3 has a. threaded bearing aperture 10 in axial alinement with the boss 9. The casing cover 11 has its inner face circumi erentially rabbeted to provide a cylindrical shoulder 12 to fit within the cylindrical inner edge of the rib 7, and a Hat inner peripheral portion 13 outside the shoulder 12 to fit against the fiat face 5 of the casing body 1.

The contiguous faces 5 and 13 of the casing body and cover may be provided with registering grooves preferably greater in one dimension cross sectionally than the other, thus forming an annular packing chamber 14 to receive an annular packing member 25. The member 25 is preferably circular in cross section but may be of any desired cross sectional shape, it being necessary only that the cross sectional dimension of the packing in the direction of the axis of the pump be slightly larger than the cross sectional dimension of the chamber 14 in the same direction. It will thus be seen that when the cover is tightly fitted to the casing body the packing tightly engages both the cover and the casing body and may be compressed and deformed throughout the length of the chamber l l, thus insuring a tight engage- Inent between the packing and casing and cover throughout the circumference of the packing. By having the chamberv 14: of greater dimension .in one direction cross sectionally, room is provided to contain the deformed packing so that the packing will not be pinched between the contiguous faces 5 and 13 of the cover and pump body, thus insuring a metal to metal contact and an lit accurate fitting of the casing walls with respect to the rotor. Concentric with the shoulder 12, the cover 11 has upon its inner face a relatively low annular rib 15 of the same diameter as the opposed rib 8 of the casing body.

By way of example, the rotor casing herein disclosed is one having ribs between which the rotor has a close working fit and rotates. lit is to be understood, however, that the ribs may be mounted upon the rotor and the walls of the casing be straight, so that in effect there is produced an outer annular water passage, in which the water is engaged by the blades or buckets of a rotor. There must be a relatively close Working fit between the rotating member and the casing, otherwise relatively high pressures cannot be built up in such passage, for it would short circuit from the discharge or pressure end of the passage directly to the suction or inlet end of the passage. However, the clearance between the rotor and the casing may be varied somewhat depending upon the conditions and purposes of the pump. The preferred construction is that herein shown, in which the ribs are mounted on the casing walls and the rotor has a portion engaging between the ribs, for in this case the rotor which is the moving part has less weight and also has less surface to be engaged by the pressure of the water in a fluid channel, and consequently less pressure is transmitted to the bearings.

A shaft 16 is journaled axially in the casing body and cover and in bearing members mounted in the tubular boss 9 and in the aperture 10 in the bracket A rotor 17 is fixed to the shaft 16 within the casing. The rotor 17 is a circular disk having a hub .18, a web 19 and an outer thickened peripheral portion 20 upon the outer ed es of which" are formed the impeller tectl 21. Relatively large apertures 22 are formed in the web 19 of the rotor. portion 20 of the rotor has a close Working fit between the annular ribs 8 and 15 of the casing body 1 and cover 11 whereby the peripheral ortion of the casing is substantially cut off rom the central portion thereof. The outlet an inlet connections communicate with the peripheral ortion of the casing and an abutment 23 etween the inlet and outlet closes the passage outside the periphery of the rotor between the inlet and outlet and has a close fit over the rotor outside the ribs 8 and 15. The abutment is thick enough to fit over a plurality of the peripheral teeth of the rotor, whereby pressure generated at the discharge outlet cannot be released by escape of water past the abutment to the inlet. A slight clearance between the ribs 8 and 15 and the rotor 12 is necessary to permit rotation of the rotor; this slight clearance will be sufiicient even The thickened menses with the closest working fit to permit a relatively slight leakage to the center of the casing in the form of a thin film of liquid which acts as a lubricant between the surfaces of the rotor and ribs. The clearance may be varied in the different sizes and designs of pumps for various purposes but it is desirable to equalize whatever pressures are created on the sides of the rotor to prevent the rotor from being forced axially in one direction or the other. If there is a slight misalinement between'the rotor and easing, a greater leakage will occur on one side of the rotor than the other, which would tend to build up a pressure on the side where the leakage is greater, which would tend to increase the misalinement. liy providing the large apertures 22 in the web the pressure is equalized on the opposite sides of the rotor.

By making the channel (3 of relatively small size and considerably smaller than the inlet and discharge lines, it will be seen that the rotor with its buckets or pockets formed between the ribs 21 will have a greater effect in carrying the water around the passage. For instance, l have found that to make the channel relatively small, as disclosed herein, a considerably higher pressure can be produced with my pump and still a good volume of water can be delivered.

Furthermore, it is to be understood that the particular forms of apparatus shown and described, and the particular procedure set forth, are presented for the purposes of explanation and illustration, and that various modifications of said apparatus and procedure can be made without departing from my invention, as defined in the appended claims.

What it claimis:

1. In a pump, a casing comprising a pair of complemental members each havin a seating f ace of substantial width adapted to contact with a corresponding seating face of the other member, a closed and endless recess formed in the zone of said seating faces and defined by said members, said recess being of'materially greater cross sectional dimension in the plane of the seating faces than normal thereto, a packing gland of deformable material adapted to be received wholly within said recess, and means for securing said casing members together with their seating faces in substantial contact to compress and deform said packing providing a liquid .seal between said faces, the cross sectional area of said packing gland being materially smaller than the corresponding eross sectional area of said recess.

2. In a pump,a casing comprising a pair of complemental members each having a seating face adapted to contact with a corresponding seating face of the other member to accurately position the members when menses assembled, a closed elongated recess defined by said complemental members when in assembled relation, and a packing member of deformable material adapted to be received Wholly within said recess and to be compressed between said members when the members are in assembled relation, said packing member normally having a materially greater minimum cross sectional diameter when in unconfined condition than the cross sectional diameter oi said recess taken normal to the seating face of the members, the cross sectional diameter of said recess taken substantially parallel with said seating tacos being materially greater than the greatest cross sectional diameter of said packing member when confined within said recess.

In a pump, a casing comprising a pair of complemental members each having a seating face of substantial width adapted to contact with a corres ionding seating face formed on the other member When said men'ibers are assembled, an endless recess defined by said compleniental members when in assembled relation, a packing member of deformable material adapted to be received wholly within said recess and to be materially compressed between said members to provide a liquid seal therebetwleen, said packing member normally having a materially smaller cross sectional area than the corresponding cross sectional area of said recess.

4. A pump casing comprising a pair of ccmplemental members each having a SGLtlr ing face of substantial width adapted to contact with a corresponding seating face of the other member, an endless groove formed in one or" said faces, a corresponding groove formed in the other of said faces and adapted to register therewith when said members are in assembled relation, the recess'defined by said complemental grooves being off materially greater cross sectional dimension in the plane of the seating faces than normal thereto, a packing gland of del'ormable material adapted to be received within said recess, and means adapted to secure said members together with their seating faces in substantial contact and adapted thereby to materially deiorm said packing gland and to provide a liquid seal between said laces 5. A pump casing comprising a pair of coniplemental members each having a seating face of substantial Width adapted to contact with a corresponding seating face of the other member, an endless groove of substantially the same uniform cross section formed in each seating lace and adapted to register when said members are assembled in order to define an endless closed recess of oval cross section, said recess being of materially greater cross sectional dimension in the plane of the seating face than normal thereto, a packing gland of deformable material and of greater cross sectional diameter than the cross sectional dimension of said recess in a direction normal to said seating faces, and means adapted to secure said members together with their seating faces in contact and with said packing gland in compressed and deformed condition wholly within said recess to provide a liquid seal between said members when said members are in assembled relation with their respective seating faces in contact.

In testimony whereof I hereunto aliix my signature.

WILLIAM E. DERPJZGK. 

